Balance mechanism for watches and clocks



Sept. 8, 1953 J. ENGLISH 2,651,170 7 BALANCE MECHANISM FOR WATCHES AND CLOCKS Filed May 26 1949 D IN V EN TOR. fins: 57ml A? Patented Sept. 8, 1953 UNITED STATES OFFICE BALANCE MECHANISM FOR WATCHES AND CLOCKS James English, Winsted, Conn. Application'May 26, 1949, Serial No; 95,509 4 Claims. (01. 58 -117) This invention relates to balance mechanism for watches and clocks and more particularly to a balance wheel and hair spring for use on such mechanisms. 7 7

An object of this invention is to provide a balance mechanism of a novel and simpler construc tion than those heretofore used.

A further object of this invention is to provide a novel hairspring for a balance mechanism which is highly efficient in its operation and less costly to produce than the conventional types of helical springs heretofore used for balance wheels-of clock mechanisms. 7 t

A still further object of this invention is to provide such a hair spring which may be readily and accurately adjusted for varying the speed of the balance wheel "in order to correct any errors in the operation of the timing mechanism.

Further objects'and advantages will be more clearly understood from the following description and the accompanying drawings in which:

Fig. 1 is a plan view showing-portions of a balance mechanism embodying my invention.

Fig. 2 is'a side view thereof partly-in section.

Fig.- 3'is a plan viewof a portion of the mec hanism shown in Fig. 1 but in a differentposition.

Fig. 4 is an enlarged fragmental top view'showing the balance wheel and related parts.

Fig. 5 is a side view' thereof showing some of the -parts in section.

, Fig/ 6 is aplan view illustrating the'operation of thebalance wheelwhenadjusted for a fast speed.

Fig. '7 is a similar view showing the-operation of the "balance'wheel when adjusted for slow speed.

As illustrated in the drawings, the numeral 5 denotes a'member forming a portion of the casing on which is mounted a frame 6 of a timing mechanism which includes a main spring,

not" shown; that drives' an escap'ement wheel 1 through a series of gears and pinions such as illustrated.

An e'scapement rocker arm 8 is pivotally mounted-in the said frame, by means of staff 9, and is rocked-by teeth on the escapement wheel I which "engage escapement cam pins on said rocker arm in "the conventional manner well known to those skilled in the' art.

The said rocker arm has a portion 10 extending therefrom with a slot therein which receives a pin H projecting perpendicularly from the balance wheel [2 for oscillating the said balance wheel in the conventional manner. The said balance wheel is pivotally mounted on the frame 6 by means of a staff 13 which rotates inpivots in said frame including the usual adjustable p ivot I l that is preferably in the form of a screw.

In the embodiment of the present invention, the balance wheel is provided with an opening 15 which extends therethrough and has parallel sides 16 and l! at opposite sides of a radial axis, as indicated at 18 in Figs.'6 and '7. a My invention also provides a novel hairspring, as illustrated at [9 in the drawings. This hair spring preferably consists of a, straight length of spring wire, which may be flat or round, and is fastened, at 20, to an end of an' adjusting lever 2| which is pivotally mounted onasupporting bracket 22 by means of"a pivot pin 23 thatjis adapted to fractionally retain';said lever in adjusted position on the bracket 22.

The hair spring |9;"proje'cts from 'the' endo the lever 2| through the opening Win the ,balance wheel and-maybe adjusted for varying the speed of said balance wheel as willbe'hereinafter described. It will be-noted, fromFigsxd' and '7, that the degree of oscillation of the balance wheel 12 will vary indirectly with the distance 'of the hair spring I9 from'theaxisofsaid wheel. "Therefore, intheposition shown in Fig.6," the hair spring, being positioned near its 'far'position relatively to the said axis, will engage the'opposite parallel walls Sand "and limit 'th oscillating movement of the balance wheel"to"thedistance to'make more strokes'per minute.

' i ls 'illustrated [in 7, the hair spring 19' is lo'c'atedjn itsiiear' position relatively to the axis of the balance "wheel 'This permits the "wheel to oscillate for the distance indicatedat (b) and thereby reduce the oscillating speed of'the balance wh''el so that it'will make fewer strokes per minute.

I Itwill be understood 'that'the oscillation {of the balance'wheel for the'distanceindicate d at (a) is enoughto move the rocker lever In for a sufficient distance to permit the intermittent rotation of the escapement wheel land that the said escapem entlwheel willmove'for'the distanceof one tooth for each oscillation of' the balance wheel regardless of whether the balance wheel oscillates for the distance (a) or (b).

In the operation of my improved balance mechanism, the hair spring 19 may be adjusted for its position relatively to th axis of the balance wheel [2 by merely swinging the lever 2| on the pivot 23 in either direction. If it is desired to increase the speed of the timing mechanism, the hair spring is moved outwardly to the position illustrated in Fig. 6 and, if it is desired to reduce the speed of said mechanism, the hair spring is moved inwardly to the position illustrated in Figs. and 7. The said lever 21 is preferably held in adjusted position by friction between it and the bracket 22, but, if desired, the pivot screw 23 may be tightened to lock the lever 21 in adjusted position.

It will be understood that the variation in the length of the oscillating stroke of the balance wheel is caused by reason of the fact that the sides 16 and I! of the opening are parallel and thereby reduce or increase the distance traveled by the said wheel in accordance with the position of the hair spring 1 9' relatively to the aXis of the balance wheel. The hair spring l9 acts merely as a resilient stop for each oscillating movement of the balance wheel and controls the distance traveled by said wheel so as to increase or decrease its stroke and thereby increase or decrease the number of strokes Per minute and" accordingly vary the speed of operation of the timing device.

It will be noted that the rocker arm 8 is formed flat and of a single piece of material and has a slot which receives the pin' I}. It will be further noted that the outer end of the slot is closed to prevent disengagement between the said arm and pin during the operation of the balancewheel. Such disengagement, if it were to occur, would not only render the clock inoperative but also render it possible to throw the clock out of beat. If the clock should be handled in a violent manner during transportation or use, and such handling causes the b a1- ance wheel to oscillate through an are greater than that permitted by the hair spring when in its downwardly inclined position, the closed slot will prevent" the pin H from becoming disengaged from the arm 8.

By constructing the rocker arm as above described, the necessity of notching the balance shaft to provide a clearancefor the rocker arm is eliminated thereby permitting the said balance shaft to be manufactured more accurately and more inexpensively.

I claim:

1. In a timing mechanism comprising a frame having an upper and a lower plate, a train of gears including an escapement wheel mounted between said plates, means for driving said mechanism, a'balance wheel operated by said escapement wheel for controlling the speed of said mechanism, and adjustable stop means for variably limiting the length of the oscillating stroke of said balance wheel to thereby increase or decrease the number of strokes per minute of said .balance wheel; said stop means including a resilient spring member pivotally connected to said frame and projecting therefrom through an opening in said balance wheel having spaced walls at opposite sides thereof abutting said spring member.

2. In a timing mechanism comprising a frame, a gear train including an escapement wheel, means for driving said mechanism, and a balance wheel for controlling the speed of operation of said mechanism; said balance wheel being pivotally mounted between said frame and deriving oscillating movement from said escapement wheel, and stop means for limiting the length of the oscillating strokes of said wheel to thereby increase and decrease the number of said strokes in a given time; the said stop means including a resilient spring member pivotally connected to the top plate of said frame and extending therefrom through an opening in said balance wheel, and cooperating linear abut- ,ments at opposite sides of said opening engageable with said spring member in different adjusted positions for limiting the length of the oscillating stroke of said balance wheel in proportion to the distance between the said spring member and the axis of the balance wheel.

3. In a timing device, a balance mechanism including a pivotally mounted balance stafi, a balance wheel supported on said staff, means imparting oscillating movement to said wheel and controlled thereby, andstop means for var riably limiting the length of the oscillating strokes of the said wheel to thereby increase and reduce the number of strokes in a given period of time; the said stop means including an opening in said wheel having spaced parallel elongated sides disposed at oppositesides of an axis extending radially from the fulcrum of said wheel, a support, a hair spring member mounted on said support and extending therefrom on a plane with the axis of said staff and through said opening for abutment with said walls to limit the length of the oscillating strokes of said wheel, and means for adjusting the said hair spring member to different distances from the axis of said stall to locate said spring member for abutment with different portions of said walls and thereby varying the length of the oscillating strokes of said wheel in accordance with the distance of said spring member from the said axis.

(l. In a timing mechanism comprising a gear train and a balance wheel for controlling the operation of said gear train, stop means for limiting the oscillating stroke of said wheel including a resilient member, and elongated spaced abutments on said wheel engageable with said member at different distances from the fulcrum thereof for varying the oscillating strokes of said wheel; the said abutments being so disposed relatively to each other that the length of the said strokes is increased as the point of contact between the resilient member and the abutments is moved nearer to the fulcrum of said balance wheel.

JAMES ENGLISH. 1 References Cited in the file of this patent f i UNITED STATES PATENTS Number Name Date 2,081,727 Bareyny May 25, 1937 FOREIGN PATENTS Number Country Date 17,187 Switzerland June 7, 1898 19,698 Switzerland May 19, 1900 28,690 Switzerland May 19, 1900 122,617 Switzerland Dec. 16, 1927 112,289 Austria Oct. 15, 1928 

